Calculation and Analysis of the Molecular Weight Characteristics of the Polymer in the Synthesis of Butyl Rubber

2022 ◽  
Vol 1049 ◽  
pp. 224-231
Author(s):  
Irina Antonova ◽  
Regina Dmitricheva ◽  
Veronika Bronskaya ◽  
Guzel Aminova ◽  
Iliya Lapin ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Molecular Weight ◽  
Catalytic System ◽  
Chain Transfer ◽  
Methyl Chloride ◽  
Chain Termination ◽  
Butyl Rubber ◽  
Chain Growth ◽  
Molecular Weight Characteristics ◽  
Cationic Copolymerization

The article compiled a mathematical model of the cationic copolymerization of isobutylene and isoprene using a catalyst AlCl3 in a CH3Cl solution, including the reactions of initiation, chain growth, chain transfer to the monomer, and chain termination. The molecular weight characteristics of butyl rubber synthesized in methyl chloride using a catalytic system based on aluminum trichloride have been investigated. Relationships are obtained for calculating the moments of the molecular weight characteristics of butyl rubber. The effect of the concentration of the initiator on the conversion versus time was investigated.

CATIONIC COPOLYMERIZATION OF ISOBUTYLENE WITH ISOPRENE: KINETICS OF THE PROCESS AND DETERMINATION OF KINETIC CONSTANTS

2015 ◽  
Vol 88 (4) ◽  
pp. 574-583 ◽  
Author(s):  
N. V. Ulitin ◽  
K. A. Tereshchenco ◽  
D. A. Shiyan ◽  
G. E. Zaikov
Keyword(s):  
Experimental Data ◽  
Molecular Weight ◽  
Cationic Polymerization ◽  
Methyl Chloride ◽  
Theoretical Description ◽  
Kinetic Constants ◽  
Molecular Weight Characteristics ◽  
Cationic Copolymerization ◽  
Kinetics Of

ABSTRACT A theoretical description has been developed of the kinetics of isobutylene with isoprene (IIR) cationic polymerization in the environment of methyl chloride on aluminum trichloride as the catalyst. Based on experimental data on the kinetics of copolymerization (isobutylene conversion curve) and the molecular weight characteristics of the copolymer of IIR, kinetic constants for the process were found. Adequacy of the developed theoretical description of the kinetics of the IIR copolymerization process was confirmed by comparing the experimental molecular-weight characteristics calculated by this description, independent characteristics, and IIR unsaturation.

scholarly journals Cationic Copolymerization of Isobutylene with 4-Vinylbenzenecyclobutylene: Characteristics and Mechanisms

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 201 ◽  
Author(s):  
Zhifei Chen ◽  
Shuxin Li ◽  
Yuwei Shang ◽  
Shan Huang ◽  
Kangda Wu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Cationic Polymerization ◽  
Transfer Reaction ◽  
Chain Transfer ◽  
Solid Phase ◽  
Random Copolymer ◽  
Glass Transition Temperatures ◽  
Cationic Copolymerization ◽  
Chain Transfer Reaction

A random copolymer of isobutylene (IB) and 4-vinylbenzenecyclobutylene (4-VBCB) was synthesized by cationic polymerization at −80 °C using 2-chloro-2,4,4-trimethylpentane (TMPCl) as initiator. The laws of copolymerization were investigated by changing the feed quantities of 4-VBCB. The molecular weight of the copolymer decreased, and its molecular weight distribution (MWD) increased with increasing 4-VBCB content. We proposed a possible copolymerization mechanism behind the increase in the chain transfer reaction to 4-VBCB with increasing of feed quantities of 4-VBCB. The thermal properties of the copolymers were studied by solid-phase heating and crosslinking. After crosslinking, the decomposition and glass transition temperatures (Tg) of the copolymer increased, the network structure that formed did not break when reheated, and the mechanical properties remarkably improved.

Modelling the Complete Molecular Weight Distribution in Chain Growth Polymerizations

2016 ◽  
Vol 1819 ◽  
Author(s):  
Ramiro Infante-Martínez ◽  
Enrique Saldívar-Guerra ◽  
Odilia Pérez-Camacho ◽  
Maricela García-Zamora ◽  
Víctor Comparán-Padilla
Keyword(s):  
Molecular Weight ◽  
Free Radical ◽  
Radical Polymerization ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Chain Transfer ◽  
Free Radical Polymerization ◽  
Experimental Program ◽  
Chain Growth ◽  
Coordination Polymerization

ABSTRACTThis work shows the development of several models for chain-growth polymerizations that admit the direct calculation of the complete molecular weight distribution of the polymer. The direct and complete calculation implies that no statistical mean values are employed as in the moments method neither numerical approximations like in the minimum-squared based methods. The free radical polymerization of ethylene (LDPE) and the coordination via metallocenes polymerization of ethylene (HDPE) are taken as examples for analysis.In the free radical polymerization case, the conventional scheme for chain-growth polymerization is adopted, with steps for initiation, propagation, chain transfer to small species and the additional step of chain transfer to dead chains [1]. The kinetic parameter are obtained from the open literature. Two kind of reactors were modelled: batch and continuous stirred tank reactor. For this last case, a simulation strategy was considered in which the run started from an initial known population of dead chains. Results show that typical non-linear polymerization profiles for the molecular weight distribution are obtained. For the coordination polymerization of ethylene via metalocenes, the standard coordination model was employed [2]. A two-site catalyst was considered and kinetic parameters reported in the open literature were used. For this study an experimental program in a lab-scale reactor was undertaken in order to obtain modelling data [3]. Results show that the standard model adequately reproduces the experimental data in the kinetic and molecular attributes of the polymer.

scholarly journals STUDY OF MOLECULAR CHARACTERISTICS OF THE PRODUCT OF ISOPRENE POLYMERIZATION ON A NEODYMIUM-CONTAINING CATALYTIC SYSTEM BASED ON MODELING BY THE MONTE-CARLO METHOD

2020 ◽  
pp. 138-148
Author(s):  
Светлана Анатольевна Мустафина ◽  
Татьяна Анатольевна Михайлова ◽  
Эльдар Наилевич Мифтахов ◽  
Владимир Анатольевич Михайлов
Keyword(s):  
Molecular Weight ◽  
Monte Carlo ◽  
Monte Carlo Method ◽  
Catalytic System ◽  
Batch Process ◽  
Molecular Characteristics ◽  
The Monte Carlo Method ◽  
Molecular Weight Characteristics ◽  
Software Product ◽  
Formed Product

В статье предложен алгоритм моделирования периодического процесса полимеризации, основанный на методе Монте-Карло. Апробация алгоритма осуществляется на примере процесса растворной полимеризации изопрена в присутствии каталитической системы на основе хлорида неодима, лежащей в основе промышленного производства изопренового синтетического каучука. В основе алгоритма лежит имитация роста каждой макромолекулы формируемого полимера и ее отслеживание. Построенная модель позволяет исследовать молекулярно-массовые характеристики полимера в зависимости от конверсии мономеров, проводить расчет молекулярно-массового распределения получаемого продукта в любой момент времени ведения процесса. На основе предложенного алгоритма разработан программный продукт для прогнозирования изменения характеристик образующегося полимера в динамике. The article proposes an algorithm for modeling a batch process of polymerization based on the Monte Carlo method. The algorithm is tested on the process of solution polymerization of isoprene in the presence of a catalytic system based on neodymium chloride. This process underlies the industrial production of isoprene synthetic rubber. The algorithm is based on the imitation of the growth of each macromolecule of the formed polymer and tracking the processes occurring with it. The constructed model makes it possible to study the molecular weight characteristics of the polymer depending on the conversion of monomers, to calculate the molecular weight distribution of the formed product at any time during the process. Based on the proposed algorithm, a software product has been developed for predicting changes in the characteristics of the formed polymer in dynamics.

Controlled/‘living’ polymerization methods

2004 ◽  
Author(s):  
Wayne Hayes ◽  
Steve Rannard
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Chain Transfer ◽  
Living Polymerization ◽  
Degree Of Polymerization ◽  
Polymer Chains ◽  
Chain Growth ◽  
Living Polymerizations ◽  
Living Nature

Chain-growth polymerizations such as free-radical polymerizations are characterized by four key processes:(i) initiation, (ii) propagation, (iii) chain transfer, and (iv) termination. If it is possible to minimize the contribution of chain transfer and termination during the polymerization, it is possible to achieve a level of control over the resulting polymer and achieve a predetermined number average molecular weight and a narrow molecular weight distribution (polydispersity). If such an ideal scenario can be created, the number of polymer chains that are produced is equal to the number of initiator groups; the polymerization will proceed until all of the monomer has been consumed and the polymer chain ends will remain active so that further addition of monomer will lead to continued polymerization. This type of polymerization was termed a ‘living’ polymerization by Szwarc in 1956 and represents one of the ultimate goals of synthetic polymer chemists. Flory determined that in the absence of termination, the number of propagating polymer chains must remain constant and that the rate of polymerization for each growing chain must be equal. In this situation, the number average degree of polymerization (DPn) and hence the molecular weight of the polymer can be predicted by simple consideration of the monomer to initiator ratio (see eqns (1) and (2), respectively). Several key criteria are used to elucidate the ‘living’ nature of a polymerization. For a polymerization to be considered ‘living’, the rate of initiation must exceed the rate of propagation. Therefore, all the propagating polymer chains are formed simultaneously and grow at the same rate. If this situation did not occur, the first chains formed would be longer than those initiated later and the molecular weight distribution of the propagating chains would broaden. In addition, an ideal ‘living’ or ‘immortal’ polymerization must not exhibit any termination of the propagating polymer chains over the lifetime of the reaction. Consequently, ‘living’ polymerizations are characterized by very narrow molecular weight distributions (Mw/Mn < 1.2).

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